Requires: 1433454372-16356-1-git-send-email-jsnow@redhat.com
          [0/10] block: incremental backup transactions

It's entirely possible to use the incremental backup primitives to
achieve a differential backup mechanism, but in the interest of
ease of use, I am proposing the explicit addition of the mechanism
because it does not particularly complicate the code, add new edge
cases, or present itself as difficult to test.

This series actually adds two ease of use features:

(1) Add a copy primitive for bitmaps to add flexibility to the
    backup system in case users would like to later run multiple
    backup chains (weekly vs. monthly or perhaps incremental vs.
    differential)

(2) Add a 'differential' backup mode that does what the name says
    on the tin.

==
For convenience, this branch is available at:
https://github.com/jnsnow/qemu.git branch differential-backup
https://github.com/jnsnow/qemu/tree/differential-backup

This version is tagged differential-backup-v1:
https://github.com/jnsnow/qemu/releases/tag/differential-backup-v1
==